Process of subjecting fibers to the action of gases



May 9, 1933. I v H. JOHN ET AL ,9 PROCESS OF SUBJECTING FIBERS TO THEACTION OF GASES I Filed Sept. 25, 1928 2 Sheets-Sheet 1 mwwLjiam Afzz/enzra Hmnfa/zn Clarence ale/(dare y 1933- H. JOHN ET AL I 1,907,548

PROCESS OF SUBJECTING FIBERS TO THE ACTION OF GASES Filed Sept. 25, 19282 Sheets-Sheet 2 fZZAffZZfJ H0225 JZfin Z! 27 23 Clarence CZe/ZZwvPatented May 9, 1933 HANS JOHN ANDCLARENCE C. LE FEB'VRE, OF APPLCET'ON,WISCONSIN, ASSIGNORS TO PAPER PATENTS COMPANY, OF NEENAH, WISCONSIN, ACQRPORATION OE WIS- CONSIN PROCESSDF SUBJECTING FIBERS TO THE ACTION OFGASES Application filed September 25, 1928.

The invention relates to treatment of fibres by gases and isofparticular value in paper manufacture where certain undesirableencrusting materials are to be eliminated or re moved from the fibres ofthe pulp before the latter is used in making up the furnish or batchused in the actual production of the sheet.

Usually, the removal of the encrusting materials from the fibres in thelater stages of the preparation of the pulp is effected as an incidentto the bleaching process, and the 1nvention is thereforeof obvious valuein the so-called bleaching operation. However, 1t may be also employedin connection with a prior step or stage of fibre treatment whichordinarily precedes the actual bleachlng of the pulp and is notconsidered properly 1ncluded in the actual bleaching operatlon.

The invention is, in certain of its aspects, a modification orimprovement upon the invention described in the co-pending applicationof Hans John. Serial No. 273,474, filed in the United States PatentOifice under date of April 28. 1928 now abandoned. I

The principal objects of the present invention are: to provide animproved process and apparatus by meanslof which fibres may be treatedby a gaseous mediumetficiently and economically to effect removal ofencrusting or other undesirable materials capable of beinp acted upon bysaid gas; to provide an apparatus of relatively large capacity comparedwith fioor space occupied by said apparatus; to provide process andapparatus capable of ready adjustment or control so to suit variousconditions encountered in operation and various kinds or conditions ofthefibres which are to be treated, and, in general, to provide animproved, eflicient and economical process and apparatus of thecharacter described.

In the drawings, we have illustrated one form of apparatus by means ofwhich the improved process may be efficiently practiced.

In said drawings:

Figure 1 is a vertical elevation of the main parts of the apparatus,certain parts being broken away or shown in section to illustrate theinterior construction;

Serial No. 308,266.

Figure 2 is a section taken on the line 2-2 of Figure 1, and

Figure 3 is a section taken on the line 3-3 of Figure 1.

The apparatus and processwillbedescribe as used in the preparation ofpulp from wood fibres, for example, hemlock stock. In the preparation ofsuch pulp, the wood sticks are de-barked, cut up into chips andsubjected to any usual digesting process, after which the digested andwashed product is conducted to a de-watering or thickening apparatus,which preferably may comprise what in the gaper trade is designated asan Oliver filter.

uch filter is adjusted to turn out a rather heavy sheet of about 25%consistency; i. e., one pound of sheet contains one-fourth of a pound ofbone dry fibres.

After the sheet or web leaves the Oliver filter, it is comminuted orshredded by any suitable form or type of macerating device, therebyconverting the same into shreds or pieces of relatively small size; say,not to exceed an inch or two in the greatest length or width. N0difficulty is encountered in efi'ecting cutting or shredding of the web,

as the same, when it leaves the filter, is quite limp and fragile. Infact, a web of 25% consistency will not ordinarily support its ownweight if more than ten feet or so in length. In this condition the'crumbs or shreds are characterized by a high porosity, in which theindividual fibers are separated from each other and the spaces betweenthe fibers are unoccupied by liquid. In this condition the material isideally adapted for gaseous bleaching, inasmuch as the gas may readilyact upon eachindividual fiber, as the.

moist fibers are separated and are not sur rounded by liquid.

The shredded pulp or web is conducted progressively, and preferablycontinuously to the top-or inlet of the apparatus disclosed in thedrawings. Said apparatus, as to its principal elements. comprises avertical tower or chamber having its interior constructed of a materialwhich will not be in- ]uriously affected Or acted upon by the gas,preferably chlorine, which isused for the treatment. Said chamber, inthis instance,

is made of superposed sections of chemical stoneware, the varioussections 10, 11, 12, 13, 14, 15 and 16 having suitable spigot and socketjoints sealed with some plastic material which will also resist theaction of the treating gas and will at the same time provide a gas-tightjoint between the various sections of the gas chamber or tower.

In order to furnish large capacity, the treatment tower may be made ofconsiderable length in its horizontal cross-section as compared with itswidth, and to facilitate examination and to observe the action of thegas upon the material, Windows, as at 17 and 18, may be provided in thewalls of some of the stoneware sections. The top section 10 is closed atits top except for an inlet slot or trough-shaped opening 19 extendingall the way across the major dimension of its horizontal cross sectionand into which trough the shredded pulp is fed by a belt or othersuitable feeding equipment.

The lower end of the bottom section 16 of the tower extends into andsome distance below the surface of a bath 20 contained in a tank or vat21 which need not be of stoneware, but may be made of wood or otherrelatively cheap material. The said tank 21 is made of considerable sizeso as to provide room for a pair of paddle wheels 22 and 23 havingbeater blades as at 24 which serve to break up the treated pulp which isdischarged from the lower end of the tower. Said beater Wheels 22 and 23are mounted upon parallel horizontal shafts 25 and 26 rotating insuitable journals in the sides of the vat 21 and extending outwardlythereof. Said shafts. 25 and 26 are geared together by a belt or chain27 and are actuated by a pulley 28 and belt 29 operated by any suitablesource of power.

The dilution tank 21 which, except for the portion occupied by the lowersectionl6 of the tower, is open to the atmosphere, is equippedwith adischarge spout 30 by which the treated and diluted pulp is deliveredfrom the apparatus ready for further treatment or finishing.

Clear wateris fed into the tank or vat 21 by means of a pipe 31extending through the side wall of the bottom section 16 of the tower,preferably above the level of the bath of liquid in the vat, and isadmitted in such quantities as to dilute the pulp to the desired eddownwardly, as shown at 33, so that the discharge openings in the endsof said pipes will not be blocked by the: descending pulp.

moans In order to effect prompt removal from the upper end of the towerof any chlorine or other gas which ma by any chance ascend through thetop of t e tower, and to prevent such gas from entering the room orbuilding in which the apparatus is located, there is provided in theside walls of said section 10 of the tower a series of small slots oropenings 34 furnishing communication between the inside of the section10 and a pair of side conduits 35 and 36 formed' in integralenlargements 37 and 38 of said side walls. Each of said conduits 36communicates with one or more exhaust pipes, as at 39, which lead to afan or other suitable exhausting apparatus, preferably discharging intothe atmosphere outside of the building. Said exhaust arrangement servesonly to prevent rising gases from escaping through the inlet opening 19and does not produce any perceptible upward draft effect in the tower,since the opening 19 is relatively large compared with the area of theslots 34 and pipes 39.

Special means are provided to conduct the fibres downwardly through thetower at a prescribed rate of travel so that the gas will have theproper opportunity to exert the required chemical action; and to thisend, the tower is equipped with a pluralityin this instance, three-0fdampers, 40, 41 and '42, and cooperating inclined bafl'le plates, 43,.44 and 45. The baffle plates 43, 44 and 45 are stationary and servemerely to direct the downward movement of the pulp when such movement isallowed to occur as an incident to the actuation of the dampers 40, 41and 42 which are arranged to rotate on horizontal axes,preferably.intermittently and alternately.

The dampers 40, 41 and 42, and the bailles 43, 44 and 45,are preferablymanufactured of the same material as the tower sections or units so asto resist the chemical action of the gas, and the shafts which supportthe rotary dampers may be formed as integral parts of the dampers and ofthesame material. -As shown best in Figure 1, the shafts take the formof short studs or trunnions 46 and '47 which are journaled in bearingboxes 48 and 49 formed by enlarging the abutting portions of adjacentsuperposed tower unit sections so that the shafts and dampers may beinserted, removed or re-' placed by merely separating the towersections. It will be found advantageous to form the bearings withannular enlargements, as shown at 50, to accommodate flanges or rings 51fixed on the shaft ends. The purpose of said flanges or rings 51 is toprevent the seepage of bearing oil into the tower. Any oil which obtainsaccess to the ring 51 or enters the enlargement 50 may be withdrawnthrough a drain conduit 52 at the bottom of said chamber 50. Thebearings themselves memes are oiled through oil pipes 53. However, inmost cases, very little oil will be required, or water may be used as alubricant since the rotation of the dam er shafts is relatively slow. Asshown in igure 1, the dampers are driven from one side only, the otherend of the shaft being completely enclosed, as shown. Rotation isimparted to the dampers and their driving ends through shafts 54, and56,.each of said shafts being preferably of metal and united to thetrunnion ends 46 in any suitable manner. Said shafts 54, 55 and 56 maybe supported by pedestal bearings 57, 58 and 59.

The shafts 54, 55 and 56 are actuated by the following mechanism: On asuitable support, there are mounted at the respective sides or ends ofthe apparatus journal boxes 60 and 61 for rotatably supporting ahorizontal shaft 62, which shaft is continuously driven by any suitablesource of power not shown herein. On the left-hand end of said shaft 62(see Figure 1), there is fixed a sprocket 63, which through a chain 64drives a sprocket 65 keyed to a jack shaft 66 mounted to rotate on ahorizontal axis in an intermediate bearing 67 of the pedestal 58. Theother end of said shaft 66 is rotatably supported in any suitablemanner.

The shafts 66 and 55 are connected by means of an intermittent drivegear train, which in the present instance comprises a mutilated spurgear 68 keyed to the shaft 66 and a. driven pinion 69 meshing with theteeth 70 of gear 68 and keyed to the shaft 55 on the end of the dampertrunnion. The number of teeth 70 of the mutilated gear 68 and the numberof teeth in the driven pinion or gear 69 is such that the shaft 55 willmake one-half of a complete revolution for a complete revolution of theconstantly running jack shaft 66. Also, the diameter of the spur gear 68is such that the rotation of the shaft 55 occurs during approximatelyone half or less of the cycle represented by a complete revolution ofthe shaft 66, so that the damper shaft 55 will be idle approximately onehalf of the time or more.

In order to prevent improper rotation of the damper shaft 55, anautomatically actuated locking device is employed. This comprises aplate spring 71 having itslower end secured to a fixed support 72, whileits upper end is actuated with a wedge-shaped dog 73, which, by reasonof the resiliency of the spring 71, is pressed stron 1 towards thecenter of the shaft 55. Said dog 73 is of proper shape to enterdiametrically opposed and correspondingly shaped notches 74 in a collaror disk 75 keyed to the damper shaft extension 55. With thisarrangement, it will be manifest that when the teeth of the spur pinion69 are no longer engaged by the teeth 70 of the driving gear 68, theshaft 55 will remain quiescent by reason of the engagement of the dog 73 in one of said notches 74.

In order to insure that the dog 3 will not interfere unduly with therotation of the gear 69 when it is engaged by the teeth 70, there may beemployed a small radial cam 76keyed to the shaft 66 and so positionedthat it will push back the spring 71 and release the dog 73 at about thetime when the teeth 70 mesh with the teeth of the gear 69 and commenceto rotate the shaft 55.

The lowermost damper 42 is driven in the same manner as the intermediatedamper 41,

-the shaft 62 having at its right-hand end a sprocket 77 which, througha chain 78, drives a sprocket 79 keyed to the jack shaft 80. Said jackshaft 80 is keyed to the shaft 56 by the same kind of mechanism as inthe case of the connection between the jack shaft 66 and the dampershaft 55 as has just been described.

F or a purpose which will appear later, the

dampers 42 and 40 are driven in a direction opposite to the direction ofrotation of the damper 41, and therefore it is necessary to drive theshaft 80 in a direction opposite to the direction of rotation of shafts66 and 62. To accomplish this purpose, the chain 78 is shown crossed,but in practice, if the shafts 62 and 80 are located close together, itwill be found advisable to use some other suitable form of reversingmeans, for example, an intermediate spur gear. As the dampers 40 and 42should have the same direction of movement and are to rotatesimultaneously and to remain quiescent during the same portion of thecycle of operations, it is unnecessary to provide intermittent mechanismfor the damper 40. Rotation of such damper 40. is effected by means of avertically extending chain 81 connecting sprockets 82 and 83 keyedrespectively to the shafts 54 and 56. In operation, the column ofheavier-thanair gas is maintained at or slightly above the level of thebafile 43 and below the damper 40, so that when the supply of shreddedpulp is accumulating upon the damper 40 while the same is in horizontalposition, it is not being acted upon by the gas. The height of suchcolumn is controlled by effecting proper control of the supply of gasthrough the injection pipes 32.

The dampers in each case are arranged to receive the pile or heap ofpulp upon that side of the baflle which descends when rotation occurs.This is to prevent packing of the pulp which might interfere with itsfree downward movement. The baffles 43 and 44 are so located as todirect the downward movement of the ,pulp upon the upper side of thedamper, while the baflle 45 is for the purpose of controlling thedescent of pulp into the bath 20.

In practice, it is found that it is not necessary to subject the pulp tothe action of chlorine for longer than a few minutes, which periodsuiiices in the case of most wood fibres to accomplish about 75% or moreof the desired bleaching effect; It is not advisable to attempt tocomplete the bleaching operation in a. single stage for the reason thatas bleaching progresses, the action slows up and it would not beeconomical to subject the fibres to the action of the gas for a lengthof time sufficient to complete the bleaching in this stage. Furthermore,as is well known, when pulp is left in contact with strong chlorine gasfor any considerable time, the gas attacks the fibres themselves and aserious loss of pulp results, as well as damage to the fibres.

The plup, when it is delivered into the treatment bath 20, contains somechlorine gas which is dissolved in the bath and is used up in partiallycompleting the bleaching of the pulp after the latter has been dilutedin the vat. If a white pulp is desired, the pulp which has beensubjected to the action of gas in this apparatus should receive afurther bleaching treatment for the purpose of bleaching out the balanceof the impurities or encrusting materials.

Since the action of the gas upon the fibres results in a change ofcolor, such change of viously, this may be further verified by chem-'color may be utilized for the purpose of observing the action of the gasupon the pulp, so that the supply of chlorine or rate of pulp feed maybe properly regulated so that the column of chlorine is maintained atthe proper height in the apparatus. It will be understood that there isno object in feeding an excessive amount of chlorine gas into the tower.If this is done, because of the rapid retardation of the chemical actionafter a short time, the chlorine will not be used up and will rise tothe top of the tower where itill be sucked out by the fan and wasted.

In practice, the color of the pulp in the diluting bath, usually abright orange, will indicate that the supply of chlorine is properlyco-ordinated with the speed at which the pulp is traveling through thetower. Ob-

ical test of the diluted pulp.

\Ve claim as our invention:

1. The improved process of treating paper pulp which includes subs"antially thickenng said pulp to form a relatively solid mass,comminuting said massffeedmg the comminuled mass downwardly into acolumn of gaseous chlorine, mechanically maintaining.

the material irr contact with chlorine to accomplish a substantialbleaching in .a relatively brief time, repeatedly dividng said pulp soas to present new surfaces thereof for the contact of chlorinetherewith, and

then plunging the material into a diluting bath before said material hasbeen deleteriously affected by the chlorine.

2. The improved process of treating pulp.

which comprises feeding the same in solid comminuted form throughacolumn of gaseous bleaching agent while agitating the same, the timeduring which said pulp is allowed to remain in contact with thebleaching agent being so regulated as to accomplish a substantialbleaching before the bleaching agent can deleteriously affect the pulpand thence substantially diluting said pulp with water so as to renderthe same fluid and halt deleterious reactions.

3. The improved process of treating pulp which comprises feeding thesame in substantially thickened solid comminuted form downwardly througha chamber containing a gaseous treating medium and repeated- 1y dividingsaid pulp in the course of its downward movement, whereby to provide alarge area of contact for said gas.

4:. The improved process of treating pulp which comprises feeding thesame in solid comminuted form downwardly through a chamber containing agaseous treating medium and repeatedly tumbling said pulp in the courseof its downward movement, so as to divide the mass of pulp and thusprovide a large area of contact for said gas.

5. The improved process of bleaching pulp which comprises feeding thesame in substantially thickened solid comminuted form downwardly througha chamber containing a gaseous bleaching medium and repeatedly dividingsaid pulp in the course of its downward movement, whereby to provide alarge area of contact for said gas, and promptly plunging said pulp intoa diluting bath after substantial bleaching has been accomplished, inorder to avoid deleterious reactions.

6. The improved process of bleaching pulp which comprises feeding thesame in substantially thickened solid comminuted form downwardly througha chamber containing a gaseous bleaching medium and repeatedly tumblingsaid pulp in the course of its downward; movement, so as to divide themass of pulp and thus provide a large area of contact for said gas, andpromptly plunging said pulp into a diluting bath after substantialbleaching has been accomplished, in order to avoid deleteriousreactions.

7. A process as defined in claim 3, wherein the pulp which is fedthrough the bleaching chamber is in a,porous condition. I

8. A process as defined in claim 6', whereinv the pulp which is fedthrough the bleaching chamber is in a porous condition.

HANS JOHN. CLARENCE C. LEFEBVRE.

ouurtuieure or eohuoriou.

ti e No. i,907,548. [Why e, toot.

HANS JUHN, ET AL.

It is hereby certified that error appears in the printet specificationoi theabove numbered patent requiring correction as ioiiows: Page 4,litre 86, claim 4, after "in" insert the words "substantiallythickened"; and that the said ]Letters Patent should be read with thiscorrection therein that the same may conform to the record of the easein the Patent Office. I

Signed and sealed this 11th day of July, A. D. i933,

hit it. Moore.

(Seat) i Actinztlommiesioneroi Patents.

